Machine for forging hollow metal blanks



Oct. 15, 1935. E. GIACCHINO MACHINE FOR FORGING HOLLOW METAL BLANKS Filed Aug. 31, 1953 Patented, Oct. 15, 1935 UNITED STATES PATENT OFFICE Ezio Giacchino, Brussels, Belgium Application August 31, 1933, Serial No. 687,694

8 Claims.

In accordance with my said process, l heat a portion of a hollow or tubular blank over a suit-- able length until the metal has become softened and I subject the said blank to internal pressure to expand the portion of metal which has been softened by heat. Preferably the requisite internal pressure is applied through a deformable core, such as a core of powdered graphite, inserted in the hollow blank, and coaxial pressures are simultaneously exertedon said core and on the blank, in order that metal will be fed to the expanding portion of the blank, whereby the wall thickness of the hollow body may be kept uniform. It is also anobject of my present invention to provide means whereby such coaxial pressuresmay be applied singly or simultaneously, and varied independently of each other, so that the forging operation can be controlled very accurately.

To this end, the machine embodying my invention comprises means mounted for independent actuation and adapted respectively to apply coaxial pressures to the hollow blank and the deformable core therein. These means may conveniently comprise a tubular plunger carried by a movable hydraulic cylinder which in turn is carried by the piston of a fixed hydraulic cylinder, and a second plunger mounted axially within the tubular plunger, said second plunger being carried by the piston of the movable cylinder.

This construction is simple and convenient, and it is applicable to any forging machine wherein the blank is compressed between an-anvil and a power actuated plunger, and-more particularly to forging machines according to my prior Letters Patent No. 1,772,444 datedoth August 1930 in which the blank is electrically heated between movable electrodes while forging is performed.

Referring to the accompanying drawing in which I have illustrated by way of example a machine embodying the features of my present invention:

Fig. 1 is a diagrammatical elevation of said machine and Fig. 2 is a corresponding plan view.

This machine is of the general type disclosed in my Letters Patent No. 1,772,444 and comprises a plunger 1 mounted in a hydraulic cylinder l and an anvil 6 which is also in the form of a plunger mounted in a hydraulic cylinder 9. The two cylinders 9 and ID are rigidly secured to the bed frame 12 in mutual alignment, and the blank 5 to beforged is pressed between plunger 1 and anvil 6, while a portion thereof is electrically heated. Conveniently the anvil 6 forms one electrode while the other electrode comprises a guide or vice 8 in which the blank 5 is slidably engaged. As the plunger 1 is pressed towards the anvil 6, the portion 5' of the blank comprised between the two electrodes and softened by heat, is crushed 15 against the anvil and expands laterally. By a1- .lowing the anvil 6 to move back, while pressure on the plunger is continued or varied, the shape of portion 5' of the blank may be controlled as required.

In the machine according to my present invention, thereis interposed, between plunger 1 and the blank 5, a hydraulic cylinder Ii slidably mounted in guideways 4 on the bed frame 12. To the outer end of cylinder I l is secured a tubular plunger 13, while in cylinder 1 I is a piston 15 rigid with a plunger l4 coaxial with and slidably fitted in the plunger I3. In order to partake in the movements of cylinder H, the pressure fluid pipes for controlling the operation of piston 5 comprise movable portions l6, I6 telescopically fitted in stationary casings l1, l1.

Inoperation, I place a hollow blank 5 in the vice 8 and insert therein a core 3 of deformable'or loose material, as graphite powder for example. Electric current being supplied to the electrodes 6 and 8 from a transformer I8 through suitable conductors l9, pressure is applied within cylinder ll, causing plunger l4 to engage the core 3 and force the same towards the anvil 6. At the same 40 time, or shortly thereafter, pressure applied within cylinder l0 causes plunger I3 to bear on the end of blank 5 and to force said blank also towards the anvil. Under the pressure of plunger H, the deformable core will cause the wall of blank portion 5' to expand outwardly, while the pressure exerted by plunger l3 will feed metal to the expanding wall of portion 5, thus allowing said wall to retain substantially uniform thickness while it is'being forged. By moving the anvil away from the blank, and varying the relative pressures applied on plungers I3 and I4, I am enabled to control the shape of the forged body.

I may also, in some cases, omit the plunger l4 and cause the piston l5 to force powder or fluid material directly through plunger l3 and into the hollow blank 5 during the forging operation.

While I prefer to use electrical current for heating the blank to be forged, I may also heat such 5 blank in an oven for example, in which case the general arrangement of the machine may be the same, but the current supply means may be omitted. It will be understood however that constructional changes may be made in the machine herein described and illustrated, without departing from the scope of my invention as defined by the following claims.

I claim:

1. In a machine for forging hollow metal bodies from tubular blanks, the combination of means for applying pressure to one end of a tubular blank, means for applying independent pressure to the inside of said blank, and an anvil engageable with the end of the blank remote from the first of said pressure applying means and movable in response to the operation of the latter means.

2. In a machine for forging hollow metal bodies from tubular blanks, the combination of coaxial means respectively for applying pressure to one end of a tubular blank and for applying internal pressure within said blank, an abutment for the I end of said blank remote from said coaxial means,

and means for moving said abutment.

3. In a machine for forging hollow metal bodies from tubular blanks, the combination of a guide electrode for slidably engaging a tubular blank, a cooperating end electrode adapted to serve as an abutment for one end of said blank, means for moving said end electrode axially of said blank, a tubular plunger for applying pressure to the other end of said blank, and a coaxial plunger in said tubular plunger for applying pressure within said blank.

4. In a machine for forging hollow metal bodies from tubular blanks, the combination of a guide electrode for slidably engaging a tubular blank, an end electrode for supporting one end of said blank, means for supplying electric current to said electrodes, means for moving said end electrode axially of said blank, a hydraulic cylinder and a piston in said cylinder, an outer tubular plunger coaxial with said blank adapted to transmit pressure from said piston to the end of said blank remote'from said end electrode, and an inner solid plunger within said tubular plunger adapted to apply pressure within said blank.

plying means.

6. In a machine for forging hollow metal bodies from tubular blanks, the combination of an end electrode adaptedto serve as an abutment for a tubular blank, a guide electrode adapted slidably to engage said blank, means for supplying electric current through said electrodes to the portion of said blank comprised therebetween,

means for moving said end electrode away from a said guide electrode, means for applying pressure within said blank through the end remote from said end electrode, and means for applying endwise pressure to said blank to feed metal to the heated portion of said blank.

7. In a machine for forging hollow metal bodies from tubular blanks, the combination of a-bedframe, a stationary guide electrode on said bedframe for slidably engaging a tubular blank, an end electrode slidably mounted on said bed-frame for movement towards and away from said guide electrode, means for supplying electric current to said electrodes, a stationary hydraulic cylinder on said bed-frame on the side of said guide electrode remote from said end electrode, a piston in said cylinder, 21. slidable cylinder on said bed frame connected with said piston, a piston in said slidable cylinder, a hollow plunger secured to said slidable cylinder adapted to exert pressure on the end of said blank remote from said end electrode, and a solid plunger secured to the piston in said slidable cylinder, said solid plunger being slidable in said hollow plunger and adapted to apply pressure within said blank.

8. In a machine for forging hollow metal bodies from tubular blanks, the combination of coaxial means operable to respectively apply pressure to one end of the, tubular blank and to apply internal pressure within the blank, and an abutment for the end of the blank remote from said 501 coaxial means.

EZIO GIACCHINO. 

